The detection of melanoma associated antigens in patient sera could serve as a valuable means of detection and diagnosis of the disease. Our primary objective is to develop a radioimmunoassay to detect these antigens. The project will require isolation of tumor antigens for use as a standard test system. Proteolytic digestion of tumor cells followed by chromatographic and electrophoretic procedures will be used to isolate the antigens. A chimpanzee anti-human melanoma antiserum has been produced and characterized. This reagent will be utilized in antigen isolation and for radioimmunoassay. Purified tumor antigen will be used to immunize rabbits. Melanoma patients and control sera will be studied in an effort to demonstrate the specificity and sensitivity of the radioimmunoassay. The assay is potentially valuable for early detection of new or recurrent disease. In addition, the study may provide valuable insight into the in vivo role of blocking factors. Serological diagnosis of solid tumors will also be performed. Further study of melanoma associated antigens will be attempted, in particular, the possible association of known oncornavirus antigens with human and murine melanomas will be examined. In vivo localization of antibody to tumor is prerequisite for successful serotherapy. We will study in vivo localization of the chimpanzee anti-human melanoma antibody in nude mice bearing transplanted human melanomas. In addition, the B16 murine melanoma of C57 B1/6 mice and rabbit anti-B16 antibody will be used as a model for in vivo localization.